1. Field of the Invention:
This invention relates to a concrete bridge girder support structure and also to a cantilever erection method using such a support structure.
2. Description of the Prior Art:
Heretofore, several ways have been utilized in concrete bridge girder cantilever erection method to advance a concrete bridge girder produced, on a table located behind the abutment, in unit form having a length ranging from several meters to tens of meters after the concrete has solidified for the cantilever erection method of the girder on a bridge pier. For example, it is common to utilize a pushing device installed on the bridge pier to push or pull the girder having a hand garter secured thereto in sliding contact with a sliding member placed on a temporary carrier table such as a steel table or concrete block installed on the bridge pier. It is also common to utilize a horizontal jack to push or pull, along a flat plate fixed on the bridge pier, a movable carrier table having the girder carried thereon.
However, such conventional ways present many difficulties. One of the difficulties particularly with the latter way is a limited stroke distance of sliding movement of the movable carrier table, resulting in a need for a separate vertical jack to lift up the girder when the movable carrier table is intended to return to its original position at each stroke end. Furthermore, it is required in either of these conventional ways to remove the temporary carrier table and instead place a perpetual bearing device after the girder arrives at a predetermined erection position and erected thereat. In addition, the removal of the temporary carrier table will often require trouble and uneconomical hand work because of a narrow space between the girder and the pier.